The present invention relates to an electrophotographic image forming apparatus, a developing device which is detachably mountable to a main assembly thereof and a process cartridge which is detachably mountable to the main assembly.
Here, the electrophotographic image forming apparatus is an apparatus forming an image on a recording material using an electrophotographic image formation process. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (a laser beam printer, LED printer or the like), a facsimile machine and a word processor.
The process cartridge may be a cartridge which as a unit an electrophotographic photosensitive drum and charging means, developing means or cleaning means and which is detachably mountable to the main assembly of the image forming apparatus. The process cartridge may be a caxtridge which contains as a unit an electrophotographic photosensitive drum and at least one of charging means, developing means and cleaning means and which is detachably mountable to the main assembly of the image forming apparatus. The process cartridge may be a cartridge which contains as a unit an electrophotographic photosensitive drum and developing means and which is detachably mountable to the main assembly of the image forming apparatus.
In an image forming apparatus using an electrophotographic image process, such a process cartridge is used. This is because the maintenance of the apparatus can be carried out in effect by the user without the serviceman, so that operativity is remarkably improved. Therefore, the process cartridge type is widely used in the field of the image forming apparatus.
Conventionally, in a supply type developing device in which an electrostatic latent image on an electrophotographic photosensitive drum is visualized with a two component developer comprising toner and carrier, a serviceman supplies into the developing device the carrier and the toner (start material) which have been mixed at predetermined ratio before the developing device is used, and then the developing device is loaded into the main assembly of the image forming apparatus, or only the carrier is contained in the developing device in a sealed manner, and after the developing device is loaded into the main assembly of the image forming apparatus, the toner is supplied until the predetermined mixing ratio is reached.
Accordingly, it is a principal object of the present invention to provide a developing device, a process cartridge and an image forming apparatus, wherein the handing thereof is easy.
It is another object of the present invention to provide a developing device, a process cartridge and an image forming apparatus wherein a developer which is a mixture of toner and carrier is contained in the developing device.
It is a further object of the present intention to provide a developing device, a process cartridge and an image forming apparatus, wherein the developing device is a type using two component developer, and the developing device contains start material from the beginning, so that starting operation is easy, and the time required for waiting for the toner content reaching the predetermined level can be avoided.
According to an aspect of the present intention, there is provided a developing device for developing an electrostatic latent image electrostatic latent image ed on an electrophotographic photosensitive member, the developing device is mountable to a main assembly of an electrophotographic image forming apparatus, said developing device comprising; a developing member for developing the electrostatic latent image formed on the electrophotographic photosensitive member; a first developer accommodation portion for accommodation a developer comprising toner and carrier to be used for developing the electrostatic latent image; a second developer accommodation portion for accommodating a developer comprising the toner and the carrier to be supplied to said first developer accommodation portion, wherein said second developer accommodation portion is provided with an openable discharging opening, and by opening said discharging opening, the developer accommodated in said second developer accommodation portion is supplied into said first developer accommodation portion; a supply opening for supplying the toner to said first developer accommodation portion.